The Use of Sugarcane Bagasse in PP Matrix Composites: A Comparative Study of Bagasse Treatment Using Calcium Hydroxide and Sodium Hydroxide on Composite Strength

Sugarcane fibers have been studied as reinforcement fibers to develop biocomposites of sugarcane fibers-polypropylene (PP). In this study, two different alkaline solutions were used to modify the sugarcane bagasse fibers, i.e. 10% v/v NaOH and 14% v/v Ca(OH)2 solution for 4 hours. Sugarcane fibers filled to polypropylene (PP) matrix was 3 cm, 5 cm and as their original length. They were added in the various weight percentage ratios between sugarcane fibers to PP of 20/80, 25/75, and 30/70. Fourier-Transform Infrared (FTIR) spectroscopy was used to study the chemical structure of bagasse fibers after treatment. Composite strength was measured by tensile test which was performed in accordance with ASTM D638-03. The fracture surface of tensile tested composite specimens contained fibers from both treatment was evaluated using Scanning Electron Microscope (SEM). Results from the tensile test show that performing NaOH treatment for 4 hours could increase the tensile strength of the composites to 24.92 MPa when original length sugarcane fibers was used in the 25/75 weight ratio. Meanwhile the highest strength of 11.30 MPa was obtained when 5 cm fibers treated with Ca(OH)2 were added in a weight % ratio of bagasse fibers/PP at 25/75. The strength of composites decreases when bagasse fibers were added to 30 wt.%. The SEM evaluation shows the mixture between sugarcane fibers and PP was not quite homogeneous. In addition to that is a greater number of fibers were found with the transversal orientation or perpendicular to the direction of tensile stress.